Monitoring torsion in power tools and other rotating machinery is often desirable. In the case of corded power tools, such as nutrunners or screwdrivers, the monitored data permits measurement of the rotational torque output and thereby calculation of output produced by the tool. However, there are serious technical challenges in implementing a robust, economical battery-powered (cordless) power tool, particularly for precision uses. A battery operated tool is low in voltage and therefore, to be sufficiently powerful, operates with high current and/or high power density. In addition, the compact nature of a hand-held cordless power tool, coupled with the fast-changing high currents and economic cost goals, present significant circuit reliability challenges, including signal and/or noise interference, dynamic motor control issues, and thermal management challenges.